.modal-mask {
  position: fixed;
  left: 0; top: 0; right: 0; bottom: 0;
  background: rgba(0,0,0,0.18);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
}
.modal-box {
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 4px 24px rgba(0,0,0,0.18);
  padding: 32px 36px 24px 36px;
  text-align: center;
}
.modal-box h2 {
  margin: 0 0 12px 0;
  color: #1976d2;
}
.modal-box .btn {
  margin-top: 18px;
} 